Dipper-dredge.



A. W. ROBINSON.

DIPPER DREDGE.

APPLICATION FILED SEPT. 29, 1910.

Patented Apr. 1, 1913;

WITNESSES COLUMBIA PLANOORAPH C0.,WASHINGTON. D- C.

FFTQE.

ARTHUR W. ROBINSON, 0F MONTREAL, QUEBEC, CANADA.

DIPPER-DREDGE.

Specification of Letters Patent.

PatenteolApi'.il,19Jl8.

Application filed September 29, 1910. Serial No. 584,464.

To all whom it may concern Be it known that I, ARTHUR TV. ROBINSON, of Montreal, in the Provinceof Quebec and Dominion of Canada, have invented a certain new and useful Improvement in Dipper-Dredges, of which improvement the following is a specification.

My invention relates, generally, to appliances of the class, comprehending dredges and steam shovels, in which the hoisting mechanism is mounted directly upon a swinging boom, and, more particularly, to the saddle block and coordinating parts for carrying the dipper arm.

The object of my invention is to provide a simplified and improved construction to provide simple and efficient means for carrying the single dipper arm in the saddle block, with provision for ready removal and compensation for wear as from time to time desired.

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings: Figure 1 is a plan or top view of a dredger boom; Fig.

2 is a longitudinal central section through the same; and, Fig. 3 is a transverse section, on an enlarged scale, through the same, on the line a a of Figs. 1 and 2.

My present invention embodies in its main features, and constitutes an improvement upon, the general principle of certain of the constructions which are set forth in Letters Patent of'the United States Nos. 708,588, 708,589, and 708,590, all granted and issued to me under date of September 1, 1902. As in Letters Patent No. 708,588, a boom, 2, which comprises two connected side members, of tapering form, secured at their lower and larger ends to a turn table, 3, which is journaled to rotate in a suitable bearing on the hull of a dredge. A solid or single dipper arm, 4, which passes through the boom, carries, on its lower end, the usual dipper, and is, as in Letters Patent No. 708,589, raised and lowered, as required for the performance of the work of the dipper, by two parallel lines of hoisting rope, 6, 6 which are, however, differently disposed from those of Patent No. 708,589, and are actuated by hoisting mechanism, located, as in Letters Patent No. 708,590, at the base of the boom, but of improved construction as hereinafter described. Two sheaves, 7, 7 are fixed upon a shaft, 7 which is ournaled in bearings at the point or outer end of the boom, 2, said sheaves being set sufiiciently far apart to allow the dipper arm, 4, to pass between them. The two lines of hoisting rope, 6, 6 which are attached to the lower end of dipper arm 4, thence upwardly and over the sheaves, 7, 7 and thence downwardly to a hoisting drum, 9, journaled near the base of the boom, to which drum their ends are made fast. The hoisting drum, 9, is made of such length as to admit of the two parallel lines of hoisting rope, 6, 6*, being simultaneously wound upon its end portions, leaving its middle portion, the length of which is substantially equal to the width of the di oper arm, 4, unoccupied by rope. A single ioisting gear, 9*, secured on the middle port-ion of the drum, is actuated by a hoisting engine, 10, fixed to the base of the boom, to raise the dipper arm and dipper by the following intermediate mechanism. A pinion, 11 which meshes with the gear, 9, is fixed to the actuating member of a friction clutch, 12, and is mounted loosely therewith on a countershaft, 11, in order to be free to revolve when the members of the clutch are disconnected, so as to allow the dipper arm and dipper to drop when required. The countershaft, 11, carries a gear, 11 which engages a pinion, 10 on the shaft, 10 of the hoisting engine, 10, and when the clutch members are connected, the rotation of the engine shaft effects the rotation of the hoisting drum, 9, and consequently the elevation of the dipper arm and dipper. The friction clutch may be of any suitable and preferred construction, many of which are familiar to engi users, and does not form part of my present invention.

The dipper arm, 4,see Fig. 8-is carried on the boom by and within a saddle block comprising two side plates, 12, 12, and a flanged top plate or separator, 12*, bolted thereto. The inner ends of the side lates are provided with eyes, 12", which are fitted freely on a shipper shaft, 13, journaled on the top of the boom. A pinion, 13 fixed on the shipper shaft, engages a rack, 14, secured to the under side of the dipper arm by countersunk head bolts, 14, and nuts, 14". The rack, 14, is provided with a central row of teeth, 14, and with a wide shrouding or longitudinal rib, 14 on each side thereof, and the pinion, 13, is

formed with a central row of teeth, 13*, of

of the bolts, 14*, which secure the rack to the dipper arm. It has heretofore been the practice to pass these bolts through the rack between the teeth, where there is insufiicient space to admit a head of proper size, the objection to which practice will be obvious.

This is especially unsatisfactory in the case of the old form of dipper arm, which is split and in two pieces, and in which the racks are necessarily very narrow. A flat plate of steel, 15, is fitted on the upper side of the dipper arm, for the purpose of acting as a bearing surface for the dipper arm on the saddle block, in sliding through the latter, and as a washer plate or bearing for the nuts, 14 of the connecting bolts. The top plate, 12, of the sliding block, is provided with lateral grooves or recesses, to enable it to clear the bolts, lt and it is firmly bolted to the side plates of the saddle block, making a complete frame which incloses the dipper arm and through which the latter can freely slide.

The shipper shaft, 13, is provided with a brake wheel or brake wheels, 13 of the usual construction, by the application of braking force to which the shaft can be held stationary, or the dipper arm be allowed to slide freely through the saddle block while revolving the shipper shaft and pinion, accordingly as may be desired. The position and radius of working of the dipper is thus controlled in the ordinary manner, as is familiar to those skilled in the art.

The single dipper arm with the rack having the wide lateral shroudings permits the bolts securing the rack to the dipper arm to be disposed so that they canbe tightened at any time; the saddle block entirely clears the boltsand provides a sliding surface be tween the rows of bolts for the bearing of the dipper arm; and the parts are constructed and related so that they can be readily taken up and assembled as conditions may require.

I claim as my invention and desire to secure by Letters Patent:

In an excavating appliance of the class set forth, the combination of a swinging boom, a saddle block comprising two side plates having eyes for coupling it to the boom, and a top plate having internal grooves and lateral flanges above said grooves through which it is bolted to the side plates, a dipper arm fitted to traverse through the saddle block and to bear on the top plate thereof, a rack provided with a central row of teeth and lateral longitudinal shroudings, countersunk head bolts passing through said shroudings and through the dipper arm, nuts engaging said bolts within the grooves of the top plate, and a pinion journaled' on the boom and provided with central teeth engaging the teeth of the rack and lateral shroudings abutting against the shroudings thereof.

ARTHUR W. ROBINSON.

Witnesses:

VALENTINE J. R. CHRISTIAN, FRANoIs E. M. ROBINSON.

Copies 01' this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, I). G. 

